Process for increasing selectivity of tetramethylene glycol

ABSTRACT

THE SELECTIVITY OF TETRAMETHYLENE GHYCOL, BY THE HYDROGENATION OF Y-BUTYROLACTONE, IS INCREASED BY USING A CATALYTICALLY ACTIVE METALLIC NICKEL-METALLIC COBALT-OXIDE OF THORIUM.

United States Patent O 3,772,395 PROCESS FOR INCREASING SELECTIVITY F TETRAMETHYLENE GLYCOL Mitsuo Yamaguchi and Yoichi Kageyama, Tokyo, Japan, assignors to Mitsubishi Chemical Industries, Ltd.,

Tokyo, Japan NoDrawing. Filed Aug. 26, 1971, Ser. No. 175,359 Claims priority, application Japan, Aug. 6, 1970, 45/ 77,667 Int. Cl. C07c 31/18 US. Cl. 260 -635 D 5 Claims ABSTRACT OF THE DISCLOSURE The selectivity of tetramethylene glycol, by the hydrogenation of 'y-butyrolactone, is increased by using a catalytically active metallic nickel-metallic cobalt-oxide of thorium.

BACKGROUND OF THE INVENTION Field of the invention Description of the prior art It is known to form TMG by the hydrogenation of the corresponding v-BL, in the presence of a catalyst. This reaction has not, however, been conducted satisfactorily on an industrial scale.

The conventional catalysts used 'in that reaction are usually characterized by relatively low reaction activities. Although certain catalysts are known which have a higher activity, it has been found that they rapidly lose their high activity within short operating periods.

Another' difficulty with the hydrogenation technique for the production of TMG, is that large quantities of tetrahydrofuran (hereinafter referred to as THF) and by-products butyl alcohol and propyl alcohol, are also produced.

A need exists, therefore, for a high activity catalyst which does not lose its high activity in a short period of time. A need aiso exists for a catalyst which will improve the selectivity of the hydrogenation reaction to increased production of TMG. a

SUMMARY OF THE INVENTION Accordingly, it is one object of this invention to provide a process for hydrogenating 'y-BL to form TMG whereby the'selectivity .for the formation of TMG is high, and which process can be used advantageously on an industrial scale.

It is another object of this invention to provide a high activity catalyst, "which remains highly'active 'over a relatively extended period of time.

These and other objects'have'now herein been attained by hydrogenating 'y-butyrolactone. in .contact with a catalyst containing metallic nickel, metallic cobalt, andoxide of thorium.

DETAILED DESCRIPTION OF THE EMBODIMENTS The catalyst used for this invention contains three catalytically active components, metallic nickel, metallic cobalt and oxide of thorium; The term oxide of thorium is meant to include not only thorium oxide, but also other oxides of thorium as well. The ratio of the three components may be 1:0.02-10:0.04-l0 by weight of NizCozThO and preferably, 1:O.10.1-6 of NizCo: ThO Although oxides of thorium have been used in catalytic compositions previously, they are ordinarily only used as carriers. In contradistinction, the oxides of thorium in the present invention provide certain synergistic effects when combined with metallic nickel and cobalt, and hence they provide the dual function of both carrier and catalytically active component. This difference is a significant characteristic of this invention.

The starting materials for preparation of the catalytically active composition of this invention is not critical. Preferably, preparation of the composition can begin with a variety of nickel compounds, cobalt compounds and thorium compounds which are easily converted into metallic nickel, metallic cobalt and oxides of thorium by heat, in various operations involving drying, oxidizing or reducing. For example, suitable for the preparation of the catalyst are inorganic salts, e.g., nitrate, chloride, and organic salts, e.g., formate, acetate or hydroxide of nickel, cobalt or thorium.

The catalytically active components can be used without any additional carrier. However, the components are preferably supported on a carrier. When a carrier is used, it is suitable to use highsiliceous content materials, such as silica, silica-alumina, kieselguhr and pumice. Best results are obtainable by'using a'carrier having an Si0 content of more than The reason for the good results with SiO as the carrier is not clear. However, it is believed that the SiO,, affects the catalytic mechanism of the Ni-Co-ThO composition. The amount of catalytically active components carried on the carrier may be from 1:0.1-50, and preferably 1:1-10 by weight of metallic nickelzcarrier. The technique for supporting the catalytic composition on the carrier is not critical and any conventional technique may be used to achieve this result. For instance, support can be obtained by conventional impregnation, atomization, precipitation, coprecipitation, etc. Impregnation, however, is relatively simple and results in a catalyst system which provides highly reproduceable reaction results.

In preparing the catalyst by coprecipitation, a mixture of kieselguhr in an aqueous solution of nickel nitrate, cobalt nitrate and thorium nitrate is prepared and an ammonia solution is added dropwise to said mixture while stirring.

In preparing the catalyst by precipitation, nickel, cobalt and thorium hydroxide are precipitated onto the surface of kieselguhr. Theresulting product is washed with water, dried and reduced with hydrogen to prepare a catalyst containing kieselguhr as the carrier and metallic nickel, cobalt and an oxide of thorium as the catalytically active components.

H Interestingly, when thoriumhydroxide or thorium nitrate are reduced with .hydrogen,.the result is thorium oxide and not metallic thorium.

In preparing the catalyst by impregnation, kieselguhr is impregnated with an aqueous-solution of nickel nitrate and cobalt nitratev and Lthorium nitrate, and then is dried and calcined in air.

In the present catalytic composition, nickel is the principal catalytically active component for the hydrogen reduction reaction. Cobalt is a promoter for improving the reduction activity and the oxide of thorium functions to synergistically improve the reaction-selectivity to TMG and to promote the catalytic activity of the composition at high temperatures tor extended periods of time.

In conducting the reaction using the catalyst of this invention, it is desirable to effect the reaction between certain defined limits. When the reaction temperature is too high, the reaction is too severe and various decomposition products may be produced, thereby adversely affecting having a volume of 200 cc. and then hydrogen was supplied under pressure. The reaction was conducted at a reaction temperature of 250 C. under 100 atm. total pressure, for 6 hours. The resulting product was cooled and was analyzed by gas-chromatography. As a result, it was the yield. Accordingly, it is desirable to effect the reaction found that 58.1 g. of TMG and 0.7 g. of tetrahydrofuran between 150 and 400 C., and preferably 200300 and a small amount of decomposition products of propan- C., at a pressure of 50-600 atmospheres, and preferably 01, butanol, etc. were produced. The yield of TMG and l00-500 atmospheres of hydrogen pressure. THF were, respectively, 98.0 mole percent and 8.7 mole The recation time has a close relationship with tem- 10 percent. It was found that the activity of catalyst of this perature and pressure, etc., and should be controlled deexample was not decreased for more than 2,000 hours by pending upon the selected conditions of temperature and the life test in the fixed-bed continous reaction process. pressure, and is usually 1-15 hours. E LES A solvent may be used during hydrogenation to im- XAM P 2 6 prove the uniformity and ease of reaction by removing The Process for p f TMG of Example 1 Was the exothermic heat of reaction. Suitable solvents which repeated, except changmg e catalyst and reaction c imay b d f hi purpose are those hi are Stable tions. The results are shown in Table 1, together with the under the reaction conditions and include dioxane, results ExamPle acetone, tetrahydrofuran, methanol, ethanol, etc. The The ylelds of TMG and by'product were p amount of solvent used can be discretionally selected, but uvely calculated by the following formula: is preferably 0.1-10 times the amount by weight to the mole of TMG 1 resulting product. Yle d of TMG mole of starting material of y-BL The reaction can be carried out either in batch X100 (percent) operations or continuously. The reaction can also be conducted in a. plurality of steps. Suitable catalyst Yield of by-product mediums for the reaction include fixed-bed systems, movtotal of each carbon mole of ing-bed systems, fluidized-bed systems, etc. atom of byproducts by product As stated above, when 'y-BL is hydrogenated in accarbon atoms of startin cordance with this invention, the catalyst maintains high Xmole of 'y-BL material 'y-BL activity for a relatively long time and TMG can be effectively produced on an industrially acceptable scale. These X100 (P TABLE 1 Condition of reaction Yield Selec- Catalyst Pres- By- Uuretivity sure TMG THF product acted TMG Composition Carrier Temp, atmos- Time, (per- (per- (per- 'y-BL (per- Autoclave Ex Ni-Co-ThOz CarzCat C. pheric hrs. Solvent cent) cent) cent) (percent) cent) charging 1 5:20:10 1 65:35 250 100 4 None. 98 1.6 0.5 98 'y-BL cc. charge Cat. 20 g. charge. 2 l0:10:5 75:25 210 500 4 Dioxane-- 85 4 2 9 93.4 Solvent 50 cc.

'y-BL 50 C. Cat. 20 g. 3 5:25:20 50:50 280 150 2 N0ne.. 71 5 1 23 92.2 'y-gLtfigocc. 8. u 4 30:5:5 :40 270 400 3 Methanol- 89 6 2 3 91.8 Solvent 5ti cc. 'y-BL 50 cc. Cat. 20 g. 5 20=20=10 50:50 250 300 1 None-- 50 1 1 48 96.1 0%. 20g. 'y-BL e 10:5:5 s0=2o 200 200 10 Hexane--. 69 1 0.5 30 98.6 soiv ii't 50 cc. 'y-BL 50 cc. Cat. 20 g.

1 Kieselguhr carrier. 1 Silica carrier. 8 Silica-alumina carrier (silica:alumina=85:15). 4 Unreacted 'y-BL was less than 0.5%. advantages can be shown by comparison with the same EXAMPLE 7 process using conventional catalysts. 55

Having generally described the invention, a more com- I The catalyst of active components of Ni-Co-ThO havplete understanding can be obtained by reference to ing the ratio of l0:10:5 by weight of NizCozThO and certain specific examples, which are included herein for carrier of 75% by weight of kieselguhr was packed in a purposes of illustration only and are not intended to be reactor. 'y-BL was continuously supplied together with bylimiting unless otherwise specified. 6O drogen at an average temperature of 230 C. in a EXAMPLE I packed layer, under a pressure of 300 atm. The results are as follows:

Nickel nitrate, cobalt mtrate and thorium nitrate in a ratio of 5:20:10 parts by weight as metal nickelzmetallic cobaltzthorium oxide, were dissolved in 10 parts by weight of water at 80 C. parts by weight of kieselguhr was 65 533;? f fi immersed in the solution and was dried at 80-1'00 C.

Aft 10h t for 10 hours. The product was then calcined at 350 C. Ait i 200 iigiiis? 3 for 4 hours in air to cause decomposition, and was MW 400 11mm Percent 86 92 reduced at 400 C. for 8 hours. in an atmosphere of hydrogen gas. The resulting catalyst consisted of a carrier of kieselguhr and a catalytically active Nico-Th0; (5-20-10 by weight). The ratio of the catalytically active components to the carrier was 35:65 by weight.

50 cc. of 'y-BL and 20 g. of said Ni-Co-'I'hO /kieselguhr COMPARATIVE EXAMPLE A catalyst was prepared according to Example 1 except the oxide of thorium was replaced with titanium oxide.

catalyst were charged into a shaking type autoclave The process for hydrogenating 'y-BL of Example 1 was repeated, except using said catalyst. The results were as follows:

unreacted 'y-BL 67 It is clear that the yield of TMG was quite low and the selectivity of TMG was quite low.

Having now fully described the invention, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the invention.

Accordingly, what is claimed as new and intended to be secured by Letters Patent of the United States is:

1. A process for producing tetramethylene glycol Which comprises hydrogenating 'y-butyrolactone in the presence of a catalyst consisting essentially of metallic nickel, metallic cobalt, and an oxide of thorium as the catalytically active components wherein the ratio of metallic nickel, metallic cobalt and oxide of thorium is 1:0.02-10:0.04-l0 by weight, and wherein the reaction is conducted at a temperature of 150400 C. and under a hydrogen pressure of 50-600 atmospheres.

2 The process of claim 1, wherein the catalytically active components are supported on a carrier.

3. The process of claim 2, wherein the ratio of metallic nickelzcarrier is 1:0l50 by weight.

4. The process of claim 2, wherein the carrier is a highly siliceous material containing more than of SiO;;.

5. The process of claim 4, wherein the reaction is conducted in the presence of a solvent.

References Cited UNITED STATES PATENTS 3,370,067 2/1968 Johnson 260346.1 2,244,196 6/1941 Herbert 252-472 FOREIGN PATENTS 870,245 3/1953. Germany 252-472 OTHER REFERENCES Moritz et al., Chem. Abst. 71, 1253611, 1969, Japan, 69 05 366.

HOWARD T. MARS, Primary Examiner US. Cl. X.R. 260346.1 

